“At his Transfiguration,” wrote St. Thomas Aquinas, “Christ showed his disciples the splendor of his beauty, to which he will shape and color those who are his: ‘he will reform the body of our lowness configured to the body of his glory’ (Phil 3:21).” It is not coincidental that on this Sunday, in which the Gospel recounts the Transfiguration, the epistle reading from St. Paul contains these words: “But our citizenship is in heaven, and from it we also await a savior, the Lord Jesus Christ. He will change our lowly body to conform with his glorified body by the power that enables him also to bring all things into subjection to himself.”

The Transfiguration, like many key events in the Gospels, points to the past, notes the reality of the present situation and then accentuates the promises to be fulfilled by God in the future. The past is obviously bound up in the presence of the two greatest prophets of the Old Testament, Moses and Elijah, who appeared and were in conversation with Jesus Christ, the prophet who had been prophetically declared by Moses: “A prophet like me will the Lord, your God, raise up for you from among your own kinsmen; to him you shall listen” (Dt 18:15). So, a great prophet promised the final and greatest prophet, and then appeared alongside in order to validate two things: the identity of Jesus and the fact that God keeps his promises.

The connections between Moses and Jesus are numerous and significant. Just like Moses, Jesus liberated his people from slavery and led them in an exodus out of bondage. Like Moses on Mount Sinai, Jesus would shine with the glory of God. And Jesus established a covenant with the new Israel, the Church, that was both new and everlasting.

The importance of covenant might not be immediately clear in the story of the Transfiguration, but the Old Testament reading brings it to the fore. God commanded Abram to bring together some animals and birds, sacrifice them, and then wait among them. Why? It goes back to when God called Abram to leave his home, land and family (Gn 12:1-3), a definitive moment in salvation history. Abram’s response in faith was foundational for what would later follow at Mount Sinai and at Mount Calvary. At the heart of Abraham’s relationship with God was the berith: the covenant. This unique relationship had to be confirmed by an oath, which solemnly bound the two parties together, and this oath involved a public sacrifice.

The covenant with Abraham was sealed with the blood of sacrifices, and the Mosaic covenant followed the same pattern (see Ex 24:1-8). And the new covenant established by Jesus Christ was sealed by his bloody, sacrificial death on the Cross. The Catechism of the Catholic Church, in the section on divine revelation, states that God, “who ‘dwells in unapproachable light,’ wants to communicate his own divine life to the men he freely created, in order to adopt them as his sons in his only-begotten Son” (No. 52). It explains how the covenants worked to restore communion with God (Nos. 54-64), culminating the Incarnation and the saving work of “Christ, the Son of God made man, [who] is the Father’s one, perfect, and unsurpassable Word” (No. 65).

The incarnate Word of God opened the doors of heaven with the key of the Cross so those filled with his life might enjoy eternal citizenship in the realm of light and glory.